Zus TPMS - root cause of leaks?

It was a pleasant surprise this past Saturday to receive the Zus TPMS kit that I ordered via Indiegogo. I proceeded to follow the instructions to install and calibrate the system. During the drive that followed, I noticed that at least two of the tires were slowly losing pressure.

I did the soapy water test, but it didn’t produce any noticeable bubbling to indicate a leak. I went ahead and removed the TPMS caps and then installed them - grasping the valve stem and tightening to the max by hand, then using the wrench to ensure they were securely fastened. I followed that by grasping the valve stem and TPMS cap while tightening the security nut behind it, then applied soapy water to test for leaks (which I didn’t find).

Next day, my son and I took the car on a 13-mile trip. Along the way, we were watching tire pressure progressively decrease in one tire - so much, that we had to pull over half-way into our trip to pump up the tire. At the time, I assumed it was a problem with that tire, as I knew I had a slow leak prior to installing the TPMS system. On our way back, we had to stop about 1/3 of the way home, where I replaced the tire with the spare.

I went ahead and had all 4 tires replaced with new ones on Tuesday. Since then, I have continued to experience leaks with the TPMS system installed. I took the car back to the tire store this morning, where they replaced all the stems and valves.

I will be running with the new tires without the TPMS over the coming days and will be frequently checking out tire pressure to rule out any issues with the tires, rims, valves, or stems. If all goes well, I will reinstall the Zus TPMS system and report back with results.

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Tires are maintain pressure, and I noticed that the stems/valves are shorter than what was originally installed. Stem length may be a contributing factor combined with the physics of centrifugal force and the mass/weight of the TPMS cap installed on them. This may also account for why others have reported cracks in the black TPMS covers. I’ll post more results/observations as the days go by.

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Thank you so much @mds for testing out ZUS STSM with all the effort.
I know this may be too much to ask, but can I have a photo of your new tires’ valve stem?

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I can do that tomorrow. I wish I’d taken a “Before” photo of the 1st stems installed on the new tires yesterday, as they were noticeably longer than these newer ones they installed today. Keep in mind that I have yet to attempt to install the TPMS on these new stems, as I want to ensure there is not a leak issue before introducing a new variable.

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Also may I have screenshots of the tire history pages separately for FR FL RR RL
This could help us judge if the app is functioning as it used to be.

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Here are the new valve stems on the new tires:

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Here are the screen shots from within the Zus app for each tire (set for last 7 days):

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Hi @mds did they say anything at the tire store regarding your old valve stems?

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They didn’t say a damned thing. So, while the pressure held overnight after taking it back to the store for the leaking tires, I did experience vibration in the car when I drove it over 62mph, but it was a very short distance. I asked my wife to drive it the next morning, and we now had a very mad mama bear.

She took the car to another tire store and explained the rough ride, to which they stated that they felt sure it sounded like the tires weren’t balanced when reinstalled the second time. She took it straight to them and was quite firm and assertive about her displeasing experience with what should have been a simple new tire install and wheel alignment that was now dragging on to its 3rd day.

That was about 1:15pm. When they told her they’d have it ready by 8pm, she let them know it had to be ready no later then 5pm, as we had other plans for the evening. I had to call Pep Boys Corporate and lodge a complaint about the ordeal. We got the call that the car was ready for pickup at 4pm!

I will probably reinstall the Zus TPMS this weekend - once we make sure that there aren’t any other problems introduced by the shop.

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That’s really an awful experience. Hilarious though you call her " mama bear". @mds
When we were in the early stage of development, I had similar experience when the Rear Right tire was drastically leaking air. I watched the psi dropping from 30 something all the way down to 20 something and yet on that day we planned a journey to another nearby city. My husband immediately turned on his “papa bear” mode. Luckily we found a tiny tire shop that fixed the problem in less than 30 mins.
Really thank you for being so patient in going through all this. The STSM you have in your hands are way more superior than the version that caused mine to leak and thus I really hope to see your further testing on this.
Have a nice weekend.

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Hello Julieta - do you think that the air leaks could appear only on highway speeds because the sensor size an weight? And if the leak is between the valve stem and the tire rim - it would be a nightmare to find it - you can’t simulate these working conditions on the bench or even at the tire shop on their balance machines.
Do you had leaking valves situations during the product tests?
I am asking because I am waiting for mu ZUS TPMS to arrive after a few weeks… i hope…

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@Zhivko_Nikolov I have not noticed any leaks at high speeds. I have had my sensors installed for a couple months now with no problems with any sensors leaking. Really wierd that @mds tires keep losing air. Hope they can figure it out.

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Can I ask, have any one had an issue with the sensor leaking? I’ve received my new tire monitoring system but when I install the sensors all hiss. Now I did put the security but on. Is that something I shouldn’t use? It’s a little frustrating. If I tighten them they his. Can anyone give me some advise? I can’t believe all four sensors would be defective. I’m sure I’m doing something wrong.

Thanks

In my case the tires hissed/leaked air only for the short amount of time when the TPMS was not tightened enough. Kind of like when you put the valve on to fill up your tires.

Now, that doesn’t mean you should over-tighten the TPMS sensors on your tires. Just that “on the way” to full tightness they hissed briefly in my case.